Soil processes and ecological services in the karst critical zone of Southwest China

Lead Research Organisation: Rothamsted Research
Department Name: Sustainable Agriculture Sciences-NW

Abstract

The SPECTRA programme seeks to enhance the sustainable development of one of the poorest regions of China, Guizhou, through cutting edge critical zone science undertaken by integrated, complementary and multidisciplinary teams of Chinese and UK scientists. The key question for management of the karst landscapes of SW China is "how can the highly heterogeneous critical zone resources be restored, to enable sustainable delivery of ecosystem services?"

We know little about the geological, hydrological and ecological processes which control soil fertility and soil function in these landscapes and how best to manage them to maximise ecosystem service delivery. SPECTRA has been designed to address these questions through a suite of 4 interlinked workpackages.

The CZ will span a gradient from undisturbed natural vegetation through to human perturbed and highly degraded landscapes. Using cutting-edge approaches we will integrate measurements of:

(1) the three-dimensional distribution of plants (including roots), soil, fungi, and microbes;
(2) rates of rock weathering, elemental release and soil formation processes;
(3) rates of erosion and soil redistribution; and,
(4) pools and fluxes of soil organic C (SOC), nitrogen (N) and phosphorus (P).

This will allow us to identify the biological controls on nutrient availability, soil formation and loss in the CZ and their response to perturbation, providing the rich evidence base needed to inform land management decision-making in the Guizhou province. In doing so, SPECTRA will directly address the Newton Fund objective of enhancing economic development and social welfare by providing rigorous applied scientific knowledge that will underpin the development of strategies to improve net ecological service delivery from the karst landscape, informing realistic economic and ecological compensation plans to alleviate poverty, particularly for the households that rely on fragile soils for a living.

The project is also designed to maximise the benefits to the science communities of both countries, thereby bringing significant institutional benefits to all partners. Training of Chinese Early Career Researchers in state-of-the-art approaches and techniques in leading UK laboratories is an absolute priority of the scientific partnership, and combined with the networking opportunities between project partners in the global CZ community, will contribute significantly to meeting the Newton Fund objective of building the capacity for CZ Science in China.

The ultimate beneficiaries of this project will be the people of Guizhou karst region (population 35 million), which is one of the poorest regions in China with a GDP less than 50% of the national average. In response to the environmental deterioration and changing social conditions in the Guizhou karst region, the Chinese government has intervened to promote the abandonment of the most degraded cultivated land and its succession to grassland, shrub and forest. This strategy has met with mixed success and is not yet underpinned by well-developed plans to repay landowners for rational and sustainable use of land resources. This must be informed by science that quantifies current and potential ecosystem service delivery. There is significant potential for our research on the response, resilience and recovery of the karst critical zone to perturbation to inform improved land management strategies that will meet these demands, leading in turn to improved delivery of ecosystem services to the communities in this region and higher environmental quality, addressing poverty and the welfare of the population through development of long-term sustainable economic development.

Planned Impact

In the long term the indirect beneficiaries of this research will be the general population of the Guizhou karst region (~35 million people). This is one of the poorest regions in China with a GDP less than 50% of the national average. The karst landscapes of the region are very susceptible to perturbation, and many parts of Guizhou province have suffered severe land degradation due to deforestation and inappropriate agricultural practices. Subsequently, this area currently has very limited potential for the development of sustainable agriculture to meet the demands of contemporary local population pressures. The region has also seen the migration of young adults to the cities, leaving the elderly and very young responsible for much of the agricultural production. Thus, the Chinese government is planning to implement appropriate land management policies to address this situation, which need to be informed by robust science that quantifies current and potential ecosystem service delivery. There is, therefore, significant potential for our research to inform improved land management strategies that will meet these demands. This will in turn lead to improved delivery of ecosystem services to the communities in this region and higher environmental quality, addressing poverty and the welfare of the population through development of sustainable land resource management and long-term sustainable economic development.

More immediate and specific users of this research include state government officials, and policy makers, land managers and land users in the Guizhou region. They will benefit from a rich evidence base on which to make land management and planning decisions. At meetings in China, we will communicate the results of our research directly to these key stakeholders including the Soil and Water Conservation Monitoring Station of Guizhou and the Puding Karst Ecosystem Observation Station. At these meetings we will engage in design and development of sustainable land use strategies and policies. We will build on the highly successful farmer-scientist participant model of extension 'Science and Technology Backyard' (STB) by developing the first such programme in Guizhou. We have already engaged with and, have the support of, each of the local stakeholders and the lead scientist of the nationwide STB programme.

The integration of the new China karst CZO within the international CZ programme will provide unprecedented feedback and expertise from the whole network, linking experience across scales, from the Guizhou citizen challenged by land degradation and poverty, to others across the world engaged in understanding and developing solutions to ecosystem service delivery and maintenance in a multitude of environments.

Schoolchildren in the Guizhou region of China and in the UK will also benefit from increased awareness of threats in both countries to the environment, their country's 'environmental footprint' and the need for sustainable land management, as well as educational links with schools in other countries.

Ultimately, human society stands to benefit from a deeper understanding of the karst CZ, and the need to preserve its very high aesthetic value which is depicted in many Chinese art forms. Karst is an outstanding cultural landscape because it has seen thousands of years of human occupation in harmony with the landscape, until very recently. Areas of karst in Guizhou province are part of the South China Karst UNESCO World Heritage Site, and the region boasts the world reference site for a mature karst landscape called 'cone karst'. For the local population of Guizhou, active maintenance of this unique landscape will deliver economic benefits through the national and international leisure and tourism industry.
 
Description At the end of the 20th century, China launched the 'Grain-for-Green' Project that recommended the abandonment of low-yielding sloping farmland (>15°) prone to soil degradation by erosion, to allow recovery through natural vegetative regeneration. This policy could affect soil nitrogen cycling. We found that the absolute abundance of nitrogen functional genes significantly varied according to the phase of vegetation recovery, and that concentrations of available inorganic phosphorus and nitrate were the best explanatory variables. The external N from fertilizer application promoted the absolute abundances of ammonia-oxidizing archaea (AOA) and ammonia-oxidizing bacteria(AOB) in sloping farmland. The relative abundances of chiA (associated with decomposition) increased with soil depth across all vegetation recovery phases. The relative abundances of chiA and nifH (associated with N fixation) accounted for the largest proportion (58-72%) of the measured NFGs, indicating that active N-acquisition increased along the vegetation recovery gradient. The ratios of (chiA + nifH)/(AOA + AOB) and the sums of (nirK + nirS) were larger in the forest soil than those of sloping farmland and abandoned sloping farmland, implying a greater capacity for N storage potential, though accompanied by increased gas N emission potential, in the karst forest ecosystems.
Exploitation Route The state government officials, policy makers, land mangers and land users in the Guizhou region should benefit from the findings on which to make land management and planning decisions.
Sectors Agriculture, Food and Drink,Environment

 
Description Using the Critical Zone as a framework to understand sustaining the ecosystem services of soil and water (CZO) A UK China Collaboration: adding value and increasing impact
Amount £157,333 (GBP)
Funding ID NE/S009094/1 
Organisation Natural Environment Research Council 
Sector Public
Country United Kingdom
Start 01/2019 
End 03/2021